1. Field
The following description relates to a sound focusing technology to focus sound to a particular area.
2. Description of the Related Art
Interest has grown with regards to a technology which can transfer sound to a specific listener or a particular area, without using a headset or earphones.
To focus sound on a particular area, a method of maximizing directivity of sound transferred through the air may be performed with a speaker having an ultrasonic transducer for high power/high frequency oscillation, or with a sound wave guide such as a horn and reflector.
However, it is understood that the above methods have relatively low transmission efficiency. Moreover, the above methods may induce sound distortion that may not be acceptable to general electronic devices.
In another method, an array speaker may be formed of a plurality of speakers in which a delay is assigned to a signal to be input to each of the plurality of speakers such that the direction of sound output from the plurality of speakers is focused in a given direction. This method assigns different delays to signals to be transferred to the speakers on the basis of beamforming theory or phased array antenna theory.
However, such a method requires a plurality of array speakers in order to ensure sufficient sound pressure. Accordingly, it is difficult to apply this approach to relatively smaller devices such as mobile or handheld devices.